One of the most famous comets, next to Halley's, Shoemaker-Levy 9 gave the world of astronomy a new window of information to observe, but its effect on our world did not stop there. Its impact with the planet Jupiter brought to the forefront the dangers of impacts to the world and even spurred the creation of apocalyptic genre movies such as "Armageddon" and "Deep Impact" in Hollywood.
Governmental agencies saw the devastation that comets and other large celestial objects could create thanks to this comet prompted funding for programs to watch for these NEO's (Near-Earth Objects) and to keep a close on them to ensure that we are prepared to handle them if one were to head for us. Needless to say, this little comet may not have done anything more than get caught in Jupiter's gravitation web, but its little mishap created a lot of change and awareness for the entire world.
Shoemaker-Levy 9 was the 9th comet discovered by astronomer couple Carol and Eugene Shoemaker and their colleague David Levy on March 24, 1993. The comet had gotten caught up in an orbit around Jupiter during its passing. It was the first comet to be found orbiting a planet rather than the sun and is estimated to have been doing so for 20 to 30 years prior to its sighting.
This periodic comet was photographed by the Schmidt Telescope at the Palomar Observatory in California. These images led astronomers to believe that the comet was on approach to the sun when it got caught by Jupiters pull in 1992. Jupiter's gravitational pull and its magnetic field being as powerful as it is, ripped the comet apart into smaller chunks. By 1993, Jupiter's pull brought it inward where it crashed into its atmosphere and gave astronomers and awe-inspiring sight, allowing mankind to witness a large object impact and how Jupiter acts as a protection to Earth.
Orbit Around Jupiter
Shoemaker-Levy 9 was orbiting around Jupiter at the time of its discovery. It had already been captured by Jupiter's pull since either the mid to late 60's to early 70's. As far as they can tell, Shoemaker-Levy 9 was a conglomeration of various smaller rocks that were held loosely by its own gravity and together the comet was roughly only 5 km (3.1 miles) in diameter.
As it was caught up in Jupiter's gravity, Jupiter's strong gravitational forces pulled those rocks apart. That is when the Shoemakers and Levy discovered the comet orbiting Jupiter. The first comet found to orbit a planet rather than the sun. It was orbiting the planet at a distance of roughly 49 million km (30 million miles) in an eccentric orbit of 0.9986 which is very elliptic.
After discovery, it was estimated that the comet pieces would soon collide into Jupiter's atmosphere and this sent the astronomy society into a frenzy of excitement. Never before in human history has mankind witnessed a large object impact into a planet. Preparations and anticipation began for the event so that they could observe and record the event.
As the predicted date grew near for the impact, several telescopes were pointed towards Jupiter in hopes of documenting the event including the Hubble space telescope. Galileo spacecraft was sent towards Jupiter to record the event as closely as it can along with the solar observer Ulysses spacecraft. Even Voyager 2 who was on its way out to the edge of our solar system was pointed towards Jupiter to observe the event.
Shoemaker-Levy 9 collided with Jupiter on July 16, 1994, sending fireballs out of the atmosphere on the back side of Jupiter. Only the three spacecraft recorded the actual impact but as Jupiter's orbit brought the impact zones into view, even low powered telescopes were able to see approximately 6,000 km (3,700 mi) in radius crescent shaped dark spots left from the impact. These dark spots contained hydrogen sulfide and ammonia which surprised scientist.
Galileo recorded the impact and recorded a fireball that occurred from the impact. The recordings showed the temperature from the impact reached as high as 23,726°C (42,740°F) and the fireball reached a height of 3,000 km (1,864 miles) from the planet's cloud tops. Several years after the dark spots in the clouds disappeared, Galileo approach Jupiter to find that there was still a change in the clouds from the impact. Images detected ripples in the area of the impact and the entire ring tilted 2 km (1.24 miles).
After Impact Effects
This collision and its apparent effect on a planetary system brought about much change. In 1998, the United States congress demanded that the National Aeronautics and Space Administration (NASA) maintain a program to observe and track large objects 140 meters (459 feet) or larger that are near Earth. These objects are considered dangerous to the existence of life on our planet if they were to impact with Earth. So far, there are 19,500 such objects that fit this criterion and there is a constant vigilance kept on them.
- Comet Shoemaker Levy 9 - How The Universe Works
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